The Impact of Dams on Water Scarcity: A Case Study of the Zayandehrood River Basin

Document Type : Research Article

Authors

1 Faculty of Engineering, University of Kashan, Kashan, Iran

2 Isfahan University of Technology

Abstract

Although dams are designed to regulate water extraction in river basins, environmental experts contend that excessive and poorly managed dam development can result in more harm than benefit. While dams can offer some benefits, the scale of dam construction in Iran has far exceeded what is considered sustainable. The widespread modification of river systems through damming and associated infrastructure far surpasses the water management objectives set by the Ministry of Energy, revealing a disconnect between the magnitude of infrastructure development and the effective management of water resources. This study proposes the development of a multivariate metric to evaluate the severity of sustained water stress, integrating alternative water supply sources in engineered sub-basins. The proposed index is based on entropy theory and is compared with conventional water stress indices, with key differences highlighted. Remotely sensed vegetation data are used as an independent validation tool to assess the new index. The results demonstrate that in sub-basins with minimal artificial water sources, the proposed index aligns closely with traditional drought metrics. However, in areas where engineered water supplies are present, the index provides a more accurate representation of water stress, as reflected by its ability to support vegetation growth. The results revealed that, in the upstream basin of the dam, the precipitation-based index and the combined index yielded identical outcomes in all years except for 1998. In contrast, in the downstream basin, the two indices showed divergent results in 66% of the water years analyzed.

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